The invention relates to postage meters and more particularly to postage meters of the type in which the postage meter portion including the die for printing the indicia is removable from a base which includes the platen and wherein a shutter or plate that covers the die is used to protect the indicia die from tampering whenever the postage meter is removed from the base.
A postage meter having such a shutter arrangement is described in the U.S. patent application Ser. No. 114,363 filed Oct. 27, 1987, entitled A REMOVABLE POSTAGE METER HAVING AN INDICIA COVER, assigned to the assignee of the present invention. In the shutter arrangement described in this referenced application, when the meter is properly mounted on the base, the shutter may be moved so as to uncover the die. A solenoid-operated deadbolt within the meter normally protrudes into a hole or recess in the shutter in order to prevent the shutter from being moved to expose the die while the meter is not properly installed. While this locking arrangement works well under typical conditions, there may be ways to defeat the security of this deadbolt arrangement, for example, by dropping the meter or applying other acceleration forces to the solenoid in order to jostle the deadbolt out of the recess. Since the shutter mechanism still must be actuable only when the meter is mounted on an appropriate base, there is a problem in respect of meeting each of the aspects of security constraints imposed by this type of postage meter.
It is therefore an object of the invention to provide an improved shutter locking arrangement which will inhibit unauthorized or accidental efforts to unlock the shutter by application of acceleration forces to the postage meter.
It is a further object to provide a locking arrangement wherein the deadbolt locking arrangement can not be defeated by simply pulling the deadbolt through the cover of the postage meter.